Cascading one additional transformer, from each of the five available 120 volt secondaries of an isolation trans. - to which point should the downstream transformers primary be grounded in order to :

1. Avoid the creation of a " hot chassis "

2. Avoid undue heating of all coils in the arrangement.

Should I go back to the service panel ground of the initial line supply ?

Some of these cascaded units will be quite a distance....... max 50 ft. from the base unit, with the ability to energize the base unit from the satellite, so I need to know how many, and what size conductors to lay between sites, being my main workshop room, and the garage.

I tend to lean towards overkill when it comes to safety, if such is possible.